KCNH4 encodes a pore-forming alpha subunit of voltage-gated delayed rectifier potassium channels that activates at hyperpolarized potentials and exhibits slow deactivation kinetics without inactivation 1. The channel is primarily expressed in the nervous system, with substantial overlap with other Elk family members KCNH3 and KCNH8 1. KCNH4 can form heteromultimers with other Elk subfamily channels but not with Eag, Erg, or Kv family channels 1. Beyond neuronal function, KCNH4 appears involved in cellular proliferation control, as tau protein overexpression significantly reduces KCNH4 mRNA levels in neuroblastoma cells, correlating with enhanced cell proliferation rates 23. Disease relevance includes potential contributions to intellectual disability when duplicated in 17q21.2 chr17 aberrations 4, and involvement in metabolic regulation through membrane transport mechanisms affecting milk lactose content in dairy cattle 5. Additionally, KCNH4 is implicated in feline hypokalemia as a candidate gene near WNK4 mutations 6, and its downregulation occurs in CLN1 disease cellular models, potentially contributing to altered neuronal excitability underlying epileptic phenotypes 7. These findings suggest KCNH4 functions in both neuronal excitability regulation and broader cellular metabolic processes.